Well one "solution" could be to just grab "snapshots" of the camera once a second (if it responds fast enough) then close the connection.
I have a Ring "Pro" so the battery level isn't an issue and it's able to do live-view for a few hours no problem (I tried it by leaving the windows 10 app up and running on live view for a while).
Still, if it really is running SIP the whole way, then it most likely can be accessed locally without touching their infrastructure (unless they are using something custom for the Ring-Servers -> Doorbell connection...)
I have a Ring "Pro" so the battery level isn't an issue and it's able to do live-view for a few hours no problem (I tried it by leaving the windows 10 app up and running on live view for a while).
Still, if it really is running SIP the whole way, then it most likely can be accessed locally without touching their infrastructure (unless they are using something custom for the Ring-Servers -> Doorbell connection...)